Our Fleet department is looking for a way to make our Customers digitally sign their Invoices upon delivery (most likely in a tablet / mobile device). Is this achievable via Scripting? Or do we need to purchase third party for this and if so, what would you suggest? Thank you!

It's definitely possible just via SuiteScript. In fact, when we were evaluating NetSuite years ago we asked the presales techincal consultant this very question and they came back with a POC using an external suitelet with HTML canvas that saved images back to file cabinet.

Thank you for your input @michoel